Spinal bone chisels

Abstract

A chisel with distal cutting edges, used to form channels in adjacent vertebrae, includes a shank having a longitudinal axis and a cutting head coupled to the distal end of the shank. The cutting head includes distal cutting edges, which may be linear, arcuate, or V-shaped, and a guide member, which may be hollow or formed as two spaced members, to guide the chisel into the disc space to uniformly chisel both adjacent vertebrae simultaneously to partially form a channel in the vertebrae. The guide member and cutting head may have openings for distributing cut debris to the top and bottom surfaces of the head. The guide member may also include distal transverse, longitudinal side and / or vertical cutting edges, some of which may be in stepped relationship, for further cutting the endplates and removing disc material from between adjacent vertebrae, and for scraping of endplates. Other embodiments are disclosed.

Description

[0001] This application claims the benefit of provisional application Ser. No. 60 / 513,893 filed Oct. 23, 2003, incorporated by reference herein in its entirety.[0002] This invention relates to spinal implant chisel tools and method of preparing the spinal disc space, and more particularly to spinal chisel instruments having various cutting edges for preparing the intervertebral disc space for implants. CROSS REFERENCE TO RELATED APPLICATIONS AND PATENTS [0003] Of interest are commonly owned copending provisional application Ser. No. 60 / 397,232 filed Jul. 19, 2002 in the name of David Chow et al., and PCT application Serial No. PCT / US03 / 21967 filed Jul. 11, 2003, entitled Spinal Implant Insertion Adjustment Instrument and Implants for use therewith, in the name of Osteotech Inc., all incorporated by reference herein. [0004] During spinal surgery, the surgeon may approach the spine from a variety of different orientations. One orientation uses the posterior approach, another uses the ...

AI Technical Summary

Benefits of technology

[0014] The impact hammer causes forward penetration of the chisel front cutting edge to the desired penetration depth and the impact hammer impacts the cylindrical member to cause rearward retraction of the chisel and the handle causes rearward retraction of the guide tip from the disc space. The guide tip serves as a depth gauge. Surface extensions at the rear of the guide tip prevent penetration deeper than the anterior longitudinal ligament.

[0017] U.S. Pat. No. 4,736,738 to Lipovsek et al. discloses an instrument kit and method for performing posterior lumbar interbody fusion. The kit includes first and second chisels and first and second shafts, a retaining ring with a set screw, an extraction hammer, a tamper and a hook. The first and second chisels each have a U-shaped blade and a shoulder between the blade and shaft. The second chisel is larger than the first chisel to enlarge the groove made by the first chisel. A stop prevents the shaft from slipping through the intervertebral space. The shoulders limit the depth of penetration of the chisels. The first chisel is used first and then withdrawn from the disc space. Then the second chisel is inserted to enlarge the channel formed by the first chisel. The chisel edges are coplanar and at right angles to the longitudinal axis of the instrument shaft.

Problems solved by technology

A drawback of present cutting instruments is the lack of versatility in cutting spinal material from different adjacent areas.

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